Add --with-dns option to weave run

weave

@@ -6,7 +6,7 @@ usage() {
     echo "weave launch     [-password <password>] <peer> ..."
     echo "weave launch-dns <cidr>"
     echo "weave connect    <peer>"
-    echo "weave run        <cidr> <docker run args> ..."
+    echo "weave run        [-with-dns] <cidr> <docker run args> ..."
     echo "weave start      <cidr> <container_id>"
     echo "weave attach     <cidr> <container_id>"
     echo "weave detach     <cidr> <container_id>"
@@ -402,21 +402,32 @@ case "$COMMAND" in
         docker images --no-trunc | grep $DOCKERIMAGE | grep -v latest | tr -s ' ' | cut -d ' ' -f 2
         ;;
     run)
-        [ $# -gt 0 ] || usage
-        validate_cidr $1
-        CIDR=$1
-        shift 1
+        [ $# -gt 1 ] || usage
         create_bridge
-        DNS_ARG=$(docker inspect --format '--dns {{ .NetworkSettings.IPAddress }}'" --link $DNS_CONTAINER_NAME:$DNS_CONTAINER_NAME" $DNS_CONTAINER_NAME 2>/dev/null) || true
-        DNS_SEARCH_ARG="--dns-search=."
-        for arg in $@; do
-           case $arg in
-               --dns-search=*)
-                   DNS_SEARCH_ARG=""
-                   ;;
-               *)
-                   ;;
-           esac;
+        for arg in $1 $2; do
+            case $arg in
+                [0-9]*)
+                    if [ -z $CIDR ] ; then
+                        validate_cidr $arg
+                        CIDR=$arg
+                        shift 1
+                    fi
+                    ;;
+                -with-dns)
+                    shift 1
+                    DNS_ARG=$(docker inspect --format '--dns {{ .NetworkSettings.IPAddress }}'" --link $DNS_CONTAINER_NAME:$DNS_CONTAINER_NAME" $DNS_CONTAINER_NAME 2>/dev/null) || true
+                    DNS_SEARCH_ARG="--dns-search=."
+                    for arg in $@; do
+                        case $arg in
+                            --dns-search=*)
+                                DNS_SEARCH_ARG=""
+                                ;;
+                            *)
+                                ;;
+                        esac;
+                    done
+                    ;;
+            esac;
         done
         CONTAINER=$(docker run $DNS_ARG $DNS_SEARCH_ARG -d "$@" | tail -n 1)
         with_container_netns $CONTAINER attach $CIDR >/dev/null

weavedns/README.md

@@ -8,15 +8,16 @@ the host's configured name server.
 
 ## Using weaveDNS
 
-The weave script command `launch-dns` starts the DNS
-container. Subsquently, giving any container a hostname in the domain
+The weave script command `launch-dns` starts the DNS container, and
+then you use the `--with-dns` option on containers you wish to use it.
+Subsquently, giving any container a hostname in the domain
 `.weave.local` will register it in DNS. For example:
 
 ```bash
 $ weave launch
 $ weave launch-dns 10.1.0.2/16
 $ weave run 10.1.1.25/24 -ti -h pingme.weave.local ubuntu
-$ shell1=$(weave run 10.1.1.26/24 -ti -h ubuntu.weave.local ubuntu)
+$ shell1=$(weave run --with-dns 10.1.1.26/24 -ti -h ubuntu.weave.local ubuntu)
 $ docker attach $shell1
 
 # ping pingme
@@ -39,13 +40,13 @@ If you want to supply other entries for the domain search path, you
 will need *also* to supply the `weave.local` domain or subdomain:
 
 ```bash
-weave run 10.1.1.4/24 -ti --dns-search=weave.local --dns-search=local ubuntu
+weave run --with-dns 10.1.1.4/24 -ti --dns-search=weave.local --dns-search=local ubuntu
 ```
 
 ## Doing things more manually
 
-If a weaveDNS container is running, `weave run` will automatically
-supply it as the DNS server to the new container. Similarly, both
+If you use the `--with-dns` option, `weave run` will automatically
+supply the DNS server address to the new container. And both
 `weave run` and `weave attach` will register the hostname of the given
 container against the given weave network IP address.